IBM 2361 core storage unit

IBM 2361 core storage unit

The IBM 2361, built by IBM's Poughkeepsie, N.Y. manufacturing
facilities, was installed at NASA's Manned Spacecraft Center
(MSC) in Houston, Texas, to process vast quantities of
information used by MSC-based flight controllers for the
Gemini and Apollo missions. These units had 16 times the
capacity of any previous IBM memory.

In each 2361, almost 20 million ferrite cores -- tiny
doughnut-shaped objects, each about the size of a pinhead
-- were strung in two-wire networks and packaged, with
associated circuitry, into a cabinet only five by 2 ½ feet
and less than six feet tall. The first memory was installed
for use in a complex of five powerful
IBM 7094 Model
II data processing systems. Four additional memories were
added to the NASAReal Time
Computer Complex (RTCC).

The 2361's design provided for storage of 524,000 36-bit
words and a total cycle time of eight microseconds in
each memory. The 2361 was the first IBM memory to use
two-wire core storage to increase storage capacity, improve
performance and reduce unit size.

Cores were woven into each juncture of a screen-like
mesh of wire to form a plane resembling a small window
screen. Memory circuits were associated with core planes
in the 2361 and included some 3,500 Solid Logic Technology
modules and 35,000 high-current silicon diodes. Major
feats in fabricating the 2361 included soldering and testing
180,000 connections, and welding and testing another 180,000
connections.